1. Field of the Invention
The present invention relates to an improved control device for obtaining samples from hoppers of railroad cars via an unloading gate valve arrangement.
2. Description of the Related Art
This invention is an improved device that allows a sample to be obtained from a railroad car via an unloading gate valve without fully opening the gate valve.
Railroad cars used in transporting plastic pellets or granular materials are normally provided with hoppers having a hopper discharge slot located at the bottom of each hopper. The discharge slot allows the material contained within the railroad car hopper to be unloaded. Typically, a pair of gate valves, such as the ones disclosed in U.S. Pat. No. 5,060,579 issued Oct. 29, 1991 to James W. Johnson, et al, are provided below each discharge slot as a means of opening and closing the discharge slot. The gate valves are opened and closed by means of two pairs of control handles, with one pair of handles located on either side of the railroad car. The control handles are connected to and serve to rotate a pair of operating shafts located adjacent and parallel to the discharge slot with one operating shaft located on either side of the discharge slot. The operating shafts are attached to and associated with one of the gate valves so that rotation of the operating shafts causes the gate valves to open or close, depending on the direction of rotation.
Whenever a railroad car is loaded and being prepared for shipment, the gate valves are locked in a "closed" position by locking means and the locking means are secured by seals to ensure that the shipment is not tampered with in transit. The locking means for locking the gate valves usually function by immobilizing the pair of control handles located on each side of the railroad car so that the gate valves cannot be opened. After the control handles are immobilized, seals are attached to the locking means in such a way that the seals on both sides of the railroad car must be broken for the control handles to be turned in order to open the gate valves.
Whenever the railroad car reaches its designation, the receiving agent will check the seals to make sure they are intact and will sample the load in order to assure himself of the identity and the quality of the materials before accepting the shipment and authorizing its unloading. With present control devices, it is difficult to slightly open one of the gate valves in order to obtain a sample. Thus, attempts to obtain a sample with the present gate control devices can result in partial unloading of the railroad car.
The present invention is an improved control device that allows a sample to be obtained via a gate valve by first unlocking the control handles on only one side of the railroad car and then turning one specialized control handle, i.e. a sample control handle. As the sample control handle is turned, its attached operating shaft rotates, thus, slightly opening its associating gate valve. Although the operating shaft which is being rotated connects to one of the control handles of the opposite locked pair, the operating shaft is connected thereto by means of an angled slot which allows the operating shaft to rotate sufficiently for its associating gate valve to be cracked open and a sample to be obtained through the partially opened gate valve.
3. Cross Reference to Related Applications
This application constitutes an improvement over application Ser. No. 07/882,074 filed on May 12, 1992, U.S. Pat. No. 5,188,486, for a "Quik-Loc End Arrangement For Pneumatic Gates" by the inventor of the present invention.